Background: The incidence of esophageal adenocarcinoma esophagus has risen at a rate faster than any other malignancy. This increase parallels an increased prevalence in esophageal adenocarcinoma's primary predisposing lesion, Barrett's metaplasia. The explanation for these changes has been elusive. In addition, there have been no significant outcomes studies of whether endoscopic surveillance of Barrett's metaplasia causes a significant decrease in cancer stage or improved survival. This proposal's overall goal is developing a series of investigations on the topics of Barrett's metaplasia/esophageal adenocarcinoma. These projects, combined with rigorous formal methodological training, will provide the candidate with skills in study design, case-control and cohort studies, database management, questionnaire development/implementation, survival analysis, multivariate analysis, and training in cost-effectiveness analysis. Protocols: A. Perform a case-control study and survival analysis using Northern California Kaiser Permanente (NCKP) esophageal cancer patients from 1990-1997 to determine whether use of endoscopy is associated with a lower stage of disease and improved survival. B. Perform a case-control study of patients with Barrett's metaplasia to evaluate pharmacologic and dietary risk factors for this pre-malignant condition. C. Establish the group of Barrett's metaplasia patients as a cohort for future follow-up studies of neoplastic progression, natural history, and risk stratification. When completed, this study will provide needed information on absolute risk of adenocarcinoma in different risk groups and allow completion of informed cost-effectiveness analyses of surveillance programs. Conclusion: The proposed studies, combined with formal education and mentoring, should substantially increase our knowledge of these cancers, and foster the candidate's development into an independent researcher in gastrointestinal disease epidemiology and outcomes.